Question 223289
-4-2n+4n>7-4
2n>7-4+4
2n>7
n>7/2
n>3.5 ans.
Proof:
Let n=3.6
-4-2*3.6+4*3.6>7-4
-4-7.2+14.4>3
-11.2+14.4>3
3.2>3